1. Field of the Invention
This invention relates to the manufacture of containers and primarily to the preliminary assembly of a hollow sleeve preform onto an upper extremity of a container for subsequent shrinking in situ thereon. The preform is taken in stored, flattened condition to a position immediately above the container where it is fully opened by a pair of vacuum heads and then moved into co-axial alignment with the container. The vacuum heads are pivotally partible to fully open the tubular preform and adapted to arcuate movement to co-axially align the two components for their telescopic assembly. After such initial assembly with the tubular preform no longer retained, the preform is finally deposited on the container body in precise vertical alignment. The final shrinking of the preform tightly around the container body, as can be performed by many appropriate physical conditions, is not part of this invention.
2. Description of Prior Art
This invention comprises an improvement over the methods and apparatus disclosed in issued U.S. Pat. No. 3,767,496, issued Oct. 23, 1973; U.S. Pat. No. 3,802,942 issued Apr. 9, 1974; and U.S. Pat. No. 3,959,065 issued May 25, 1976, all of which are commonly owned with the present application. In each of these disclosures, a tubular sleeve is formed which is telescopically assembled onto the article from below by a push-up mechanism. None of these disclosures pertain to a thin flexible sleeve of thermoplastic material which is stored in flattened, prefabricated condition and then opened and telescoped over the container in rapid and efficient assembly during their coincident arcuate movement.
In many of the previously-disclosed processes and apparatus for making composite containers having an integral plastic base or sleeve thereon, a manufactured glass bottle or jar is loaded onto a conveyor and pre-heated prior to mounting the plastic sleeve. The plastic sleeves are carried on an underlying turret to pass into alignment with the bottles and are moved vertically upwardly into telescopic assembly over the lower ends of the bottles. The sleeves are then carried on the bottles into a heating apparatus such as a tunnel oven wherein appropriate physical conditions shrink the sleeves into close-fitting conforming arrangement over the bottle surfaces where assembled. The heating apparatus commonly consists of a lengthwise oven through which the bottles are passed, the oven temperatures ranging from about 170.degree. F. to 800.degree. F., depending upon the plastic material selected to comprise the sleeves. U.S. Pat. No. 3,959,065, owned by the common assignee of this application, discloses method and apparatus which assure against dislocation of the sleeve on the bottle without external handling mechanism being required to hold the sleeve in place between its assembly point with the bottle and the shrinking oven.
The cap sealing of bottles has been conventionally performed in recent years to provide for reasons of sanitation, pilfer-proofing, safety and appearance, the further step of placing over and around the neck of the bottle, as well as preferably over at least part of its closure, a tubular sleeve of heat-contracting synthetic resin material, severed to a prescribed length, and then sealing the sleeve to the bottle by thermal contraction. The synthetic resin tubing is usually pressed flat and delivered in rolls in many production processes, and since the tubing may or may not stay fully flattened, particularly where it is comprised of extremely flexible and resilient material, inefficiencies can and do result when the severed lengths of tubing are fitted onto the bottle necks. In some cases, to facilitate the fitting of short, flat, tubular sleeves onto the necks of bottles, it has been common practice to preform the sleeves such as by putting perforations or scores along their fold lines. It is also possible to apply the tubes around the bottle necks without preforming the material, as taught by U.S. Pat. No. 3,861,118 to Muto; however, such method normally requires the application of a bonding agent to the bottle neck for firm adherence of the sleeve. The method and apparatus disclosed by this patent are exceedingly more complex and prone to occasionally misapply a tubular band or label. U.S. Pat. No. 2,852,899 to Murrell discloses a collar feeding mechanism which is designed to remove only the lowermost collar from a nested stack by frictional engagement with its inner surface. The collars are preformed and nested tightly into a stack from which they are deliverable onto the container necks.